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Collector used for negative pole of lithium ion battery

A lithium-ion battery and current collector technology, applied in the direction of electrode carrier/collector, can solve the problems of battery cycle attenuation, affecting the performance of lithium-ion batteries, uneven coating, etc.

Inactive Publication Date: 2011-04-27
DONGGUAN AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the process of lithium intercalation and delithiation, the volume of the negative electrode will change, so it is easier to separate the negative electrode from the current collector during the cycle, causing the battery cycle to attenuate
At present, the adhesion between the active material and the current collector is increased by punching holes on the surface of the current collector. This method will cause the active material to be coated unevenly on the surface of the current collector, which will reduce the strength of the current collector and affect the lithium ion battery. battery performance

Method used

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  • Collector used for negative pole of lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Positive electrode production:

[0019] Lithium iron phosphate (LiFePO4) is used as the negative electrode active material. A slurry containing the active material was prepared, and the solid content of the slurry contained 90% of the positive electrode active material, 5% of PVDF (polyvinylidene fluoride) as a binder, and 5% of conductive carbon as an electrical conduction aid. The slurry uses NMP as a solvent, and the weight of the solvent accounts for 30% of the total slurry weight. The slurry is evenly coated on both sides of the Al foil, and then calendered by a roller press to obtain a positive electrode membrane.

[0020] Negative electrode current collector treatment:

[0021] Copper foil is used as the negative electrode current collector body, and the treatment layer is: by weight percentage, composed of 10% conductive carbon with a D50 of 100um, 89% polyvinylidene fluoride and 1% oxalic acid. Mix the treatment layers, and stir with water as a solvent to fo...

Embodiment 2

[0027] The difference from Example 1 is that the treatment layer is: by weight percentage, composed of 5% conductive carbon with a D50 of 100um, 94% polyvinylidene fluoride and 1% oxalic acid. Other than that, the others are the same as those in Embodiment 1, and will not be repeated here.

Embodiment 3

[0029] The difference from Example 1 is that the treatment layer is: by weight percentage, composed of 20% conductive carbon with a D50 of 100um, 79% polyvinylidene fluoride and 1% oxalic acid. The printing thickness is 4nm. Other than that, the others are the same as those in Embodiment 1, and will not be repeated here.

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Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a collector used for the negative pole of a lithium ion battery. The collector comprises a collector body, wherein the surface of the collector body is covered with a processing layer. The processing layer comprises 5-20 wt% of conductive carbon, 79-94 wt% of polyvinylidene fluoride and 0.5-1.5 wt% of oxalic acid. The processing layer is adopted to deal with a negative pole collector body, and the conductivity between the collector body and negative active material can be enhanced by the conductive carbon, thereby reducing the internal resistance of the battery and increasing power performance. In processing, oxalic acid corrodes the collector body to increase the roughness of the surface of the collector body, thereby increasing the contact area, reducing contact resistance, also reducing the internal resistance of the battery, and increasing the power of the battery. The processed collector makes the adhesion between the negative active material and the collector body get better in the cycle process, makes resistance of the battery basically remain in the cycle process, and improves the cycle life of the battery.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a current collector for negative electrodes of lithium ion batteries. Background technique [0002] Lithium-ion secondary batteries have become one of the most widely used secondary batteries due to their advantages of high voltage and high energy density. With the continuous expansion of its application range, people's performance requirements are also continuously improved. Existing lithium-ion batteries generally include a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. The positive electrode sheet is composed of a positive electrode current collector and an active material coated on its surface. The positive electrode active material includes lithium cobaltate, lithium iron phosphate, manganese Lithium oxide, lithium nickel manganese oxide, and other ternary or multi-component active materials. The negative electrode sheet...

Claims

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Application Information

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IPC IPC(8): H01M4/64
CPCY02E60/12Y02E60/10
Inventor 李小芳赵丰刚吴凯崔青然朱华
Owner DONGGUAN AMPEREX TECH
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